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Benign Sleep Myoclonus in Infancy

Video demonstrates benign sleep myoclonus in infancy, a disorder of quiet sleep. Its main characteristics include rhythmic myoclonic jerks when drowsy or asleep (that stop in wakefulness), and a normal encephalogram during the episodes.

A 65-year-old man with hypophonic and dysarthric speech and masked facial expression. Vertical saccades are reduced and horizontal saccades slowed. He has moderate bradykinesia of hand movements, finger tapping, and rigidity in the limbs. Gait is stooped and slow, and his stance is narrowed and unstable. Pull test reveals minimal to no compensation.

Neuromyotonia. EMG recording from a middle-aged man includes multiple repeating discharges, each composed of multiple muscle fiber potentials with varying interpotential intervals corresponding to a firing frequency of up to 200 Hz.

Mild, abnormal ICP waveform during external ventricular drain (EVD) clamp trial with clustering of P1 to P3 waves. Respiratory variations are noted as well as Valsalva maneuver. The patient has muscle resistance testing of his deltoid, which causes the patient to perform the Valsalva maneuver and transiently increase ICP. Inspiration causes a decrease in ICP, and Valsalva maneuver during segmental muscle strength testing increases it.

The ICP waveform shown demonstrates a value of greater than 20 mm Hg and is frankly triangular with a low compliance/high elastance appearance. CSF
is drained from the external ventricular drain (EVD) system (line goes flat for a while) and is later reopened periodically. By draining CSF, this essentially changes the ICP waveform by moving
down and left on the elastance curve. Later, the ICP waveform returns after the external ventricular drain is opened and some P wave components are seen. However, it is important to recognize that the ICP waveform still has an overall noncompliant morphology indicative of a persistent abnormal intracranial pressure-volume state.

This video shows a 74-year-old woman with recurrent episodes of left functional hemiparesis. She describes acute dissociation at the onset of the symptoms and demonstrates jaw deviation to the left and left platysma contraction as part of functional facial spasm.

This video shows the patient in Case 15-1 who has right platysma contraction induced during the examination with jaw deviation to the right, which gives a superficial appearance of weakness but is actually functional facial spasm/dystonia.

A 65-year-old man with hypophonic and dysarthric speech and masked facial expression. Vertical saccades are reduced and horizontal saccades slowed. He has moderate bradykinesia of hand movements, finger tapping, and rigidity in the limbs. Gait is stooped and slow, and his stance is narrowed and unstable. Pull test reveals minimal to no compensation.

Neuromyotonia. EMG recording from a middle-aged man includes multiple repeating discharges, each composed of multiple muscle fiber potentials with varying interpotential intervals corresponding to a firing frequency of up to 200 Hz.

The ICP waveform shown demonstrates a value of greater than 20 mm Hg and is frankly triangular with a low compliance/high elastance appearance. CSF
is drained from the external ventricular drain (EVD) system (line goes flat for a while) and is later reopened periodically. By draining CSF, this essentially changes the ICP waveform by moving
down and left on the elastance curve. Later, the ICP waveform returns after the external ventricular drain is opened and some P wave components are seen. However, it is important to recognize that the ICP waveform still has an overall noncompliant morphology indicative of a persistent abnormal intracranial pressure-volume state.

This video shows a 74-year-old woman with recurrent episodes of left functional hemiparesis. She describes acute dissociation at the onset of the symptoms and demonstrates jaw deviation to the left and left platysma contraction as part of functional facial spasm.

This video shows the patient in Case 15-1 who has right platysma contraction induced during the examination with jaw deviation to the right, which gives a superficial appearance of weakness but is actually functional facial spasm/dystonia.

This video shows a patient with bilateral arm tremor. When asked to do mental arithmetic, the patient exhibits little difference in tremor. When copying cued movements in one hand, the contralateral tremor initially ceases, then entrains. Ballistic movements lead to brief pauses.

This video shows a patient who presents acutely with falls and unsteadiness on standing. She describes dissociation during the falls and is unsteady when standing, but she becomes stable when testing eye movements.

This video shows a patient describing his limbs feeling alien and artificial. He has a typical dragging gait of functional hemiparesis with the hip internally rotated. With his eyes closed, the patient’s bent foot feels straight, in keeping with a distorted cerebral map.

An 84-year-old man who has had myasthenia gravis for 3 years. The disease began with neck weakness, followed by asymmetric, bilateral lid ptosis. Examination demonstrates mild, fatigable diplopia on lateral gaze to either side, unmasked by cover/uncover maneuver.

A 64-year-old man with acetylcholine receptor antibody positive myasthenia gravis. After withholding pyridostigmine for several days, the patient has moderate right lid ptosis and horizontal diplopia at rest. These resolved within 30 seconds after injection of 2 mg edrophonium (Tensilon) and recurred 60 seconds later.

This video shows a 48-year-old man with upbeat and gaze-evoked nystagmus caused by Wernicke encephalopathy following gastric bypass surgery. The upbeat nystagmus is atypical in that it is less prominent with upward gaze. Note the gaze-evoked nystagmus on lateral gaze.

This video shows a 44-year-old man with pendular seesaw nystagmus following head trauma. The patient had a dense bitemporal hemianopia and MRI showed an atrophic optic chiasm without evidence of a compressive lesion.

This video shows a 44-year-old woman with multiple sclerosis and horizontal acquired pendular nystagmus. The patient also has vision loss in both eyes secondary to optic neuropathy. Note that the nystagmus is more prominent in the left eye, which is the eye with greater vision loss.

This video shows a 63-year-old woman with macrosaccadic oscillations following resection of a breast cancer metastasis to the cerebellum. Note that the macrosaccadic oscillations are triggered by gaze refixations and that her horizontal saccades are hypermetric.

This video shows a 55-year-old woman with opsoclonus secondary to paraneoplastic brainstem encephalitis. Note that the saccades are back-to-back, without an intersaccadic interval, and multidimensional.

Video shows a 75-year-old man
who developed gradually progressive proptosis
and ptosis in his left eye accompanied by an
oblique diplopia. Visual field loss and a relative
afferent pupillary defect ensued in the left eye as
well. Neuro-ophthalmic examination reveals that
the left eye is depressed and deviates laterally in
primary gaze. Testing of versions show a lack of
adduction and elevation of the left eye, and
limited depression which, along with ptosis, is
consistent with a left oculomotor palsy. Abduction
of the left eye is also limited, consistent with a left
abducens palsy.
The presence of a left oculomotor palsy and
an ipsilateral abducens palsy is suggestive of either
cavernous sinus syndrome or orbital apex syndrome.
In this case, however, the presence of an
optic neuropathy (not shown), which would not
occur from a cavernous sinus lesion, is the clue
that the site of the lesion is the orbital apex. The
proptosis is also most consistent with an orbital
apex mass, and MRI with contrast (see axial and
coronal images at end of video) revealed a large
left orbital apex meningioma in this patient.

This video of the same
patient as in Supplemental Digital Content 8-1
shows an exotropia (reflective of left medial
rectus weakness) and a left hypotropia (reflective
of left superior rectus and inferior oblique
weakness). Notice how the movements of the
right eye are greater than the left eye during the
test, even though it is not the paretic eye; the left
eye is unable to move because of paresis. The
deviation of the right eye (there is both an
exotropia and hypertropia) is an example of a
secondary deviation and results from the Hering
law of equal innervation, which states that an
equal force is provided to each eye.

Video demonstrates the clinical evaluation of percussion myotonia over the extensor digitorum communis. A fast strike with the reflex hammer over the extensor digitorum communis produces the characteristic extension of the fingers and wrist, with subsequent myotonic catch and delay of muscle relaxation.

Video demonstrates the characteristic paradoxical increase in myotonia with repetitive hand grips, or paramyotonia, seen in patients with paramyotonia congenita. The patient is instructed to squeeze her hand closed as tightly as she can and then open her hand quickly. This maneuver is repeated to evaluate forwarm-up of myotonia or paradoxical worsening.

Video demonstrates the difficulty in opening the eyes after forced eye closure that can be seen in patients with myotonic disorders. Eye-closure myotonia is seen most frequently in patients with sodium channel mutations. The patient is instructed to squeeze his eyes shut tightly and then open them as quickly as possible. The maneuver can be repeated to check for evidence of warm-up or paradoxical worsening.

A 52-year-old man with a clinical diagnosis of idiopathic Parkinson disease. The patient shows left-hand resting tremor with reemergence on posture and exacerbation during walking. Decrement of amplitude and speed can be seen during performance of rapid alternating movements.

A 58-year-old woman with an early clinical diagnosis of Parkinson disease who progressed to a progressive supranuclear palsy phenotype between 6 and 8 years after symptom onset (both time points shown in the video). Later development of oculomotor impairment and blepharospasm with apraxia of eyelid opening were clues regarding the revised diagnosis.

A 50-year-old man clinically diagnosed with multiple system atrophy, parkinsonian type. He is shown to have a tremorless parkinsonism with axial-greater-than-appendicular rigidity, distal-arm postural and stimulus-sensitive myoclonus, and slow, slightly wide-based gait with freezing and postural instability when turning.

A 75-year-old woman clinically diagnosed with corticobasal syndrome. Among other features, she illustrates an asymmetric parkinsonism with a markedly dystonic right arm, myoclonus, ideomotor apraxia, and cortical sensory loss.

First segment demonstrates a 36-year-old woman with cervical dystonia. Second segment shows a 72-year-old man with a 30-year history of task-specific focal hand dystonia. Motor overflow is evident when the patient writes. Third segment demonstrates lower limb dystonia in a patient with advanced Parkinson disease in the off-medication phase.

A 78-year-old woman with a 25-year history of craniocervical dystonia. Blepharospasm occurred when the patient was 53 years old, and dystonia spread to her oromandibular (at 55 years old) and cervical areas (at 60 years old).

A 5-year-old child with generalized dystonia caused by perinatal brain injury. The first symptoms appeared in the patient’s lower limbs, affecting gait, and subsequently spreading to the trunk and upper limbs.

A 32-year-old cardiorespiratory arrest survivor with action-stimulus myoclonus, magnified by the intent to move. The myoclonic jerks prevent the performance of most movements and preclude the patient’s ability to ambulate.

A 32-year-old cardiorespiratory arrest survivor with action-stimulus myoclonus. This video was taken after treatment with a combination of clonazepam and levetiracetam, added sequentially to optimize outcome.

Corticobasal syndrome due to pathology-proven Alzheimer disease in a 79-year-old man with a 7-year course of markedly asymmetric parkinsonism with aphasia. Examination at 3 years from onset demonstrates aphasia, severe ideomotor apraxia, left arm dystonia, intermittent myoclonus, and a Babinski response extensor bilaterally.

A 33-year-old man with childhood-onset motor and vocal tics that improved and nearly resolved in his twenties but returned in his thirties. As demonstrated, complex motor tics involve cervical, pharyngeal, and laryngeal muscle groups. The urge to perform tic movements was suppressible during requested performance of complex motor tasks. Although suppressibility is a functional or psychogenic feature, this patient has Tourette syndrome, with recrudescence of tics into adulthood.

A 45-year old woman with sudden-onset right hand tremor. Tremor was present at rest, with variable posturing of right hand, and during finger movements. Tremor was disrupted and its frequency changed during finger tapping with the unaffected left hand at different rates. Tremor was temporarily suppressed when engaged in the finger-nose task with the unaffected hand.

A 51-year-old man exhibiting gait impairment, right hand action tremor, and left leg resting tremor. Examination showed brief motor arrests during gait initiation and turning, steppage of the left foot, and fixed posture of both hands. While sitting, fixed hand posturing disappeared during distraction maneuvers. Leg tremor was present when the foot was resting on the anterior sole but not when resting on the heel or when unsupported. Deliberate slowness in both upper limbs was demonstrated during finger-to-nose movements and repetitive arm movements, although spontaneous movements were normal, as was writing.

A 35-year-old woman evaluated for left hemifacial spasm. Neurologic examination demonstrated reduction of left side facial spasm during distracting maneuvers. Contraction of the frontalis muscle involved the eyebrow contralateral to the spasm of the orbicularis oculi. Electrophysiologic evaluation disclosed a normal blink reflex without evidence of ephaptic transmission and disappearance of EMG contraction during sleep, by polysomnography. Psychiatric evaluation led to the diagnosis of conversion disorder.

A 54-year-old woman with paroxysmal hyperextension of the right upper limb with wrist flexion and involuntary trunk movements. During these episodes, she exhibited lateral trunk deviation to the right side. No clear precipitating factors were evident.

Video demonstrates cataplexy elicited by the strong emotional stimulus of conducting an orchestra. The patient becomes excited, has loss of muscle tone with unbuckling of the knees, and falls to the ground. Consciousness is preserved completely, and he never loses awareness. He recovers quickly, regaining his muscle strength and standing up as if he never experienced the episode.

Video demonstrates a bilateral, asymmetric, tonic seizure with semiology characteristic of frontal lobe (mesial) activation in a 32-year-old man with a normal MRI, no interictal discharges on scalp EEG, and a nonlocalizable scalp ictal EEG pattern. An ictal SPECT shows hyperperfusion in the left medial frontal lobe, so a stereo EEG evaluation is planned. The patient is medically intractable, with repetitive seizures at sleep-wake transition at bedtime most nights that have not responded to medication. The seizures routinely wake him up, but he typically can recall what happens during the seizure and responds immediately thereafter.

Video shows a 56-year-old woman with psychogenic movement of both hands at bedtime. She is alert and has no urge to move her hands. The movements interfere with her sleep onset, disappear in sleep, and reoccur upon awakening. The movements are at times also seen during the day in wakefulness.

Video demonstrates sleepwalking in a 34-year-old woman on zolpidem for chronic severe insomnia. The patient was seen by a community sleep doctor for episodes of sleepwalking and sleep smoking. She had let herself out of her house a few times, so safety was a concern. After a normal polysomnogram, the patient was started on clonazepam, which made her symptoms worse, and she was referred to a sleep center for a consultation. Video EEG showed normal N2 sleep during the entire 30-minute episode of sleepwalking (edited here for brevity).

Sleep terror in a 46-year-old woman with a childhood history of sleep terror who started having episodes of screaming in the middle of the night, to which she was oblivious. After a normal polysomnogram, she was admitted for video-EEG monitoring. EEG of this event (45 minutes after sleep onset) shows a mixture of large-amplitude very slow delta activity in the frontal and temporal leads and faster alphalike activity in the posterior leads. She responded to clomipramine but had adverse events and was subsequently put on 1 mg of clonazepam at bedtime, with which she experienced good control of the events.

Catathrenia (ie, sleep-related groaning) consists of sleep-related respiratory noises that occur predominantly during REM sleep. The typical respiratory noise in a patient with catathrenia has an expiratory quality and responds well to therapy with continuous positive airway pressure, which suggests that catathrenia may result from upper airway restriction. Between events, the patient in this video also exhibits bruxism (ie, grinding of the teeth), which is a movement disorder of sleep and may also represent an oral parafunctional activity.

Video demonstrates the Gufoni maneuver for geotropic variant of right horizontal canal benign paroxysmal positional vertigo (BPPV). The mirror image maneuver can be done for the geotropic variant of left horizontal canal BPPV.

Video demonstrates the supine roll (Pagnini-McClure) test to determine the affected side in horizontal canal benign paroxysmal positional vertigo. The side that induces the most intense horizontal positional nystagmus is presumed to be the affected side.

Spontaneous nystagmus and gaze testing in a patient who presented with acute vestibular syndrome and findings that localize to the right vestibular nerve. The patient has spontaneous left-beat nystagmus. The velocity of the nystagmus increases when he looks to the left and decreases when he looks to the right. When he looks to the right, the nystagmus does not change direction. When he looks up, the nystagmus remains left-beat. Thus, the patient has a unidirectional horizontal nystagmus.

Patient’s head is quickly moved to one side, then to the other. On movements to the patient’s left, the eyes stay focused on the target in front of him. With head movements to the patient’s right, the eyes move off the target. He then makes a voluntary corrective saccade to bring the eyes back to the target. This is considered a positive head-impulse test to the right. The corrective saccade is more obvious after some of the tests than others, likely due to variation in the speed of the movement and the patient’s ability to predict it.

Video demonstrates overt versus covert corrective saccades. In some patients, corrective saccades are easily visualized by the examiner (ie, overt saccades) whereas in other patients they may be difficult to observe or may even be imperceptible to the examiner (ie, covert saccades). This video shows examples of overt and covert corrective saccades after the head-impulse test in two patients with unilateral vestibular loss.